We tried a few different approaches at scaling beyond D20 which is as good as it gets in Chronica Feudalis. D20 perfectly fits the natural world but like I said we're modeling fire breathing creatures here.

We tried rolling an extra die with multiple ways of influencing the skills/tools/traits but it didn't feel right so we ditched it for a couple of reasons. First it always felt like we didn't have enough dice. Second and most important, it hurt the clean elegance of the core system. Keeping track of the different types of dice caused undue confusion. What was a fast clean resolution system became cluttered. The next idea was to add flat bonus to anything that was higher in scale than D20. This is what we went with.

The next step was to determine how large the bonuses should be. Bonus equal to the highest die face: +4, +6, +8, +10, +12, +20? Or the means for each die: +2, +3, +4, +5, +6, +10? After some play testing we decided to go with +1 through +5. This decision was reached because of the way the system works. A very powerful ability equates to a single die which translates into at best a single success. This means that increasingly higher bonuses give diminishing returns. Succeed by 1 or by 20 it's a single success. Something to keep in mind is that depending on the style of game any of these bonus patterns could be used and the wheels won't fly off the CF cart.

Okay, now we had the bonus pattern that felt right but we didn't want to just say D20+1. Not that it wouldn't work. It was just a matter of feel and congruity with the rest of the game. Instead went with D21, D22, and so on:

D21 = D20+1

D22 = D20+2

D23 = D20+3

D24 = D20+4

D25 = D20+5

This approach helps keep the "rule space" clean and folks from wondering why they can't get D4+1 in Riding.

For play test we didn't go with a pure agent nor a pure antagonist when writing up the dragon. Instead we went with a hybrid to get the right amount of knobs to tweak for the design phase. Here's what we came up with:

Dragon

Vigor: 4

Ardor: 3

Skills:

Chase D20

Combat D12

Parley D12

Subterfuge D12

Tools:

Ultra-Vision D21

Scales (Armor) D21

Claws D12

Breath D23

Maw D20

Aspects:

Ancient

Wily

Winged

More than once the small +1 to +3 bonus seriously gave the dragon great advantage. The bonuses were most effective when setting conditions. I knew that I could spend an action setting up a maneuver condition because of his scale.

Ticking up the D20 a couple of points after rolling really tests the bravest would-be dragon killer's resolve.

In all straight up fights the protagonists did poorly. Interestingly though the dragon was not able to stamp out his opponents in a single round by virtue of the system. Every time he took someone out it was through maneuver.

In one encounter Siggurd an Archer/Hunter/Knight rode his horse up onto the dragon's location where it was eating a stolen cow. The dragon didn't know he was there so Siggurd let loose an arrow to no avail. It was a solid blow but the scales were too much for such a mundane weapon.

The dragon swung his head around on his serpentine neck and erupted a gout of flame but Siggurd was able to use his shield against the fiery blast reducing potential harm to 1 point of vigor.

The dragon then took to flight and decided that he was going to snatch the man in his claws but it was to no avail. Siggurd drew his sword in desperation and successfully put steel between him and the ancient beast causing 1 point of Vigor loss.

Stung, the dragon went higher, pivoted and made a sweeping attack of fire. This time Siggurd didn't do so well and took a wound: Singed. Now he was down to rolling a single die.

The dragon saw his opponent dazed so he turned and successfully snatched the man in maw like a seagull snatching a morsel of food off the ocean.

Desperately Siggurd tried to use his shield to prevent the beast from dropping him but it was no use. The dragon slung him into the air, caught him again and threw him even higher.

For a moment Siggurd realized how beautiful the countryside looked from up there.

To make things a bit more heroic I'm thinking about allowing characters to break the die cap if they spend two points of Ardor for each additional die.

Also, this dragon felt like Smaug from The Hobbit. For the protagonists to have any real chance they need to know about a missing scale and require a black arrow that has never let down its owner.

Thanks for pointing me toward Vigor Rush. I had forgotten about it. It's very dramatic and would work well. I'm going to experiment a bit and see how spending Ardor to break the cap would influence things. In almost all the games so far the protagonists have lots of ardor to spare especially once they begin enduring injuries. The ardor pool might make a good "hero battery" to power high heroics.